London Youth was set up in 1887. It works with hundreds of partner organisations to help young people in London gain new skills and experience. The fields they work in include arts & culture, employability, social action, mental health & wellbeing and sports. Additionally, they offer many different courses to help build specific skillsets. They are also linked to a pair of residental centres (Hindleap in East Sussex and Woodrow in Buckinghamshire).
To see what sort of programs are offered, click this link.
The main entrance of their office is accessible, but there’s only street parking nearby.
For more charities and places in London, click this link.